Very nice site. No viruses or malicious content on the site itself. Some videos have ads in front of them that advertise a product, but those are always safe. They are Google ads. The ads you need to watch out for are the ones on the top or on the sides when you watch videos. They are 99 out of 100 times safe, but you never know. Still, very good site. I believe you need Adobe Flash player to watch the videos, though I'm not sure. It should come pre-installed on your computer when you bought it. If you somehow do not have it, you can download it here www.adobe.com/ Just go to the search box at the top right-hand corner and type in "Adobe Flash player".
Youtube is losing it when you start seeing unecessary ads on simple videos that are less than 1 minute long.
Take a look next time, youtube is gravitating towards spam ads, "you can skip this ad in 10 12 15 30 seconds" and 5 minute intervals completely kills the video you are watching and are getting into.